Cryptocurrency mining rig motherboards have, until now, mostly been based on the Intel platform because Intel chipsets put out more PCIe lanes than AMD ones, and because Intel's sub-$100 Pentium/Celeron chips don't have narrower PCIe connectivity from the CPU. ASRock apparently has a lot of unsold AMD X370 chipset inventory, and with the possible introduction of sub-$100 Ryzen chips that have 28 PCIe lanes from the CPU, a use-case has emerged for a mining motherboard based on this platform. We hence have the X370 Pro BTC+. The board features an AM4 socket, with out of the box support for "Pinnacle Ridge" processors. The socket is wired to just one DDR4 DIMM slot, but all eight PCI-Express 3.0 x16 slots.

The topmost x16 slot runs at electrical gen 3.0 x4, while the remaining seven slots are gen 3.0 x1, taking advantage of PCIe segmentation of the X370 platform. The board draws power from three 24-pin ATX, 8+4 pin EPS, and a number of Molex outputs, although most of these power connectors are optional. A point to note here is that the D-sub/HDMI display outputs only work if an A-series "Bristol Ridge" or Ryzen "Raven Ridge" APU is used (which have fewer PCIe lanes), so you're bound to take display output from one of the 8 graphics cards. A 1 GbE interface and two USB 3.0 ports make for the rest of it.